Role of HLA compatibility in pediatric liver transplantation

The influence of HLA mismatching in liver transplantation remains controversial. To date, few studies have focused solely on the pediatric population, and none have investigated DR and DQ mismatches using molecular genotyping. We sought to investigate HLA-A, -B, -DR, and -DQ mismatches in a large series of primary pediatric liver transplant recipients. Living-related liver transplants were excluded.

A total of 138 consecutive first liver transplants performed between January 1991 and July 1996 were studied. Minimum follow-up was 1 year, and both patient and graft survival rates were assessed. The incidence of the most common complications was analyzed. HLA-A and -B phenotyping was performed by complement-dependent microcytotoxicity or polymerase chain reaction (PCR)-sequence-specific primer protocols in 133 of 138 patients. HLA-DR and -DQ genotyping was performed by standard PCR-sequence-specific oligonucleotide and/or PCR-sequence-specific primer protocols in 135 patients.

Overall, there was no influence of HLA mismatching on either graft or patient survival rates. However, patients with two mismatches at the A locus showed a significantly lower incidence of acute rejection than those with one A mismatch (52% vs. 72%; P < 0.03) and patients with two B locus mismatches had a better graft survival rate at 5 years than those with one mismatch (76% vs. 62%), although this was of only borderline significance (P < 0.09). No differences were found in the severity of the episodes of rejection, incidence of chronic rejection, cytomegalovirus hepatitis, and other causes of graft loss.

This study indicates that HLA-A, -B, -DR, and -DQ mismatches are not detrimental in primary pediatric liver transplantation.